Pencil Leads

My Father trained as a draughtsman. He kept the old technical drawing set which he had used as a student in his desk. When he died I kept it in my desk. Last week I was trying to draw a circle but couldn't find a compass. I remembered the box of tools and found what I needed. There was, however, no lead in the technical pencil. Knowing that he wouldn't have left an incomplete set I unscrewed the small silver cylinder and there were the leads, where he had safely stored them over half a century before.
Thanks Dad.